Rotating electrical machine drive system

Abstract

In a system for driving a three-phase rotating electrical machine of drive sources for applying separate drive forces to a rotary shaft, a phase of the rotating electrical machine, a current of which is detected by a current sensor and capable of being used for control of the rotating electrical machine, is defined as an effective sensor-phase of the rotating electrical machine. When the number of the effective sensor-phases is one, the rotating electrical machine is driven in a one-phase control mode based on the current of the effective sensor-phase under a condition where a rotation speed of the rotating electrical machine is greater than a predetermined positive threshold, and driven by the drive forces of the other drive sources under a condition where the rotation speed is not greater than the threshold.

What is claimed is: 
     
       1. A rotating electrical machine drive system for driving at least one three-phase rotating electrical machine of a plurality of drive sources included in a rotary shaft drive system for applying separate drive forces to one rotary shaft acting on a target object or for applying the drive forces to a plurality of rotary shafts acting on the same target object in an overlapping manner, the rotating electrical machine drive system comprising:
 a specific rotating electrical machine which is one of the at least one three-phase rotating electrical machine; 
 a rotation speed calculator configured to calculate a rotation speed of the specific rotating electrical machine; 
 a control current sensor configured to detect a current of at least one phase of the specific rotating electrical machine, the detected current being used for control of the specific rotating electrical machine; and 
 a control apparatus configured to control the drive forces by controlling energization of the at least one three-phase rotating electrical machine, wherein 
 the at least one phase of the specific rotating electrical machine, the current of which is detected by the control current sensor and capable of being used for the control of the specific rotating electrical machine, is defined as an effective sensor-phase of the specific rotating electrical machine, 
 when the number of the effective sensor-phases is one, the control apparatus drives the specific rotating electrical machine in a one-phase control mode based on the current of the effective sensor-phase under a condition where the specific rotating electrical machine rotates in a forward direction and the rotation speed is greater than a predetermined positive threshold value or under a condition where the specific rotating electrical machine rotates in a reverse direction and the rotation speed is smaller than a predetermined negative threshold value, and 
 when the number of the effective sensor-phases is one, the control apparatus drives the specific rotating electrical machine by using the drive force of at least one of the plurality of drive sources other than the specific rotating electrical machine under a condition where the specific rotating electrical machine rotates in the forward direction and the rotation speed is not greater than the positive threshold value or under a condition where the specific rotating electrical machine rotates in the reverse direction and the rotation speed is not smaller than the negative threshold value. 
 
     
     
       2. The rotating electrical machine drive system according to  claim 1 , wherein
 when the control current sensor is normal, the number of the effective sensor phases is two or more; 
 the control apparatus includes an abnormality determinator configured to determine whether the control current sensor is normal or abnormal, the abnormality determinator configured to determine what the number of the effective sensor phases is when the control current sensor is abnormal, 
 when the number of the effective sensor-phases is two or more, the control apparatus drives the specific rotating electrical machine in a two-phase control mode based on the currents of the effective sensor-phases regardless of the rotation speed of the specific rotating electrical machine, and 
 when the control current sensor becomes normal, so that the number of the effective sensor-phases is reduced to one under the condition where the specific rotating electrical machine rotates in the forward direction and the rotation speed is greater than the positive threshold value or under the condition where the specific rotating electrical machine rotates in the reverse direction and the rotation speed is smaller than the negative threshold value, the control apparatus switches a drive mode of the specific rotating electrical machine from the two-phase control mode to the one-phase control mode. 
 
     
     
       3. The rotating electrical machine drive system according to  claim 1 , further comprising:
 a first rotating electrical machine configured to generate electric power by the drive force of an engine, the first rotating electrical machine and the engine being included in the plurality of drive sources; 
 a power storage device configured to store the power generated by the first rotating electrical machine, the power storage device having a predetermined charge limit value; and 
 a second rotating electrical machine which is the specific rotating electrical machine and driven with a direct-current power supplied form the power storage device, wherein 
 a rotary shaft of the second rotating electrical machine is connected to a rotary shaft of the first rotating electrical machine through a force transmission mechanism. 
 
     
     
       4. The rotating electrical machine drive system according to  claim 2 , further comprising:
 a first rotating electrical machine configured to generate electric power by the drive force of an engine, the first rotating electrical machine and the engine being included in the plurality of drive sources; 
 a power storage device configured to store the power generated by the first rotating electrical machine, the power storage device having a predetermined charge limit value; and 
 a second rotating electrical machine which is the specific rotating electrical machine and driven with a direct-current power supplied form the power storage device, wherein 
 a rotary shaft of the second rotating electrical machine is connected to a rotary shaft of the first rotating electrical machine through a force transmission mechanism. 
 
     
     
       5. The rotating electrical machine drive system according to  claim 3 , wherein
 when the number of the effective sensor-phases of the second rotating electrical machine is one, and the power stored in the power storage device is not greater than the charge limit value, the control apparatus drives the second rotating electrical machine by using the drive forces of the engine and the first rotating electrical machine under the condition where the second rotating electrical machine rotates in the forward direction and the rotation speed is not greater than the positive threshold value or under the condition where the second rotating electrical machine rotates in the reverse direction and the rotation speed is not smaller than the negative threshold value. 
 
     
     
       6. The rotating electrical machine drive system according to  claim 4 , wherein
 when the number of the effective sensor-phases of the second rotating electrical machine is one, and the power stored in the power storage device is not greater than the charge limit value, the control apparatus drives the second rotating electrical machine by using the drive forces of the engine and the first rotating electrical machine under the condition where the second rotating electrical machine rotates in the forward direction and the rotation speed is not greater than the positive threshold value or under the condition where the second rotating electrical machine rotates in the reverse direction and the rotation speed is not smaller than the negative threshold value. 
 
     
     
       7. The rotating electrical machine drive system according to  claim 5 , wherein
 when the power stored in the power storage device is greater than the charge limit value, the control apparatus causes the second rotating electrical machine to be self-driven to consume the power stored in the power storage device while driving the second rotating electrical machine by using the drive forces of the engine and the first rotating electrical machine in such a manner that the power stored in the power storage device is not greater than the charge limit value. 
 
     
     
       8. The rotating electrical machine drive system according to  claim 6 , wherein
 when the power stored in the power storage device is greater than the charge limit value, the control apparatus causes the second rotating electrical machine to be self-driven to consume the power stored in the power storage device while driving the second rotating electrical machine by using the drive forces of the engine and the first rotating electrical machine in such a manner that the power stored in the power storage device is not greater than the charge limit value. 
 
     
     
       9. The rotating electrical machine drive system according to  claim 1 , further comprising:
 a first rotating electrical machine which is the specific rotating electrical machine and configured to generate electric power by the drive force of an engine; and 
 a second rotating electrical machine included in the plurality of drive sources, wherein 
 a rotary shaft of the second rotating electrical machine is connected to a rotary shaft of the first rotating electrical machine through a force transmission mechanism, and 
 when the number of the effective sensor-phases of the first rotating electrical machine is one, the control apparatus drives the first rotating electrical machine by using the drive force of the second rotating electrical machine under the condition where the second rotating electrical machine rotates in the forward direction and the rotation speed is not greater than the positive threshold value or under the condition where the second rotating electrical machine rotates in the reverse direction and the rotation speed is not smaller than the negative threshold value. 
 
     
     
       10. The rotating electrical machine drive system according to  claim 2 , further comprising:
 a first rotating electrical machine which is the specific rotating electrical machine and configured to generate electric power by the drive force of an engine; and 
 a second rotating electrical machine included in the plurality of drive sources, wherein 
 a rotary shaft of the second rotating electrical machine is connected to a rotary shaft of the first rotating electrical machine through a force transmission mechanism, and 
 when the number of the effective sensor-phases of the first rotating electrical machine is one, the control apparatus drives the first rotating electrical machine by using the drive force of the second rotating electrical machine under the condition where the second rotating electrical machine rotates in the forward direction and the rotation speed is not greater than the positive threshold value or under the condition where the second rotating electrical machine rotates in the reverse direction and the rotation speed is not smaller than the negative threshold value.